trillion

noun

tril·​lion ˈtri(l)-yən 

1

: a number equal to 1,000 times one billion see Table of Numbers

2

: an indeterminately large number

a trillion mosquitoes out tonight

trillion adjective

trillionth

ˈtri(l)-yən(t)th 

adjective or noun

Examples of trillion in a Sentence

Recent Examples on the Web

Amid perpetual drought, population growth, and trillions of gallons of water used in desert agriculture, much of America's West is in desperate need of more rain and snow. — Daniel Manzo, ABC News, 9 Sep. 2026

Training models with trillions of parameters can require hundreds or thousands of accelerators to exchange terabytes of data. — Neetika Walter, Interesting Engineering, 8 Sep. 2026

As trillions of dollars change hands, inheritors won’t just take on their family fortunes—they’ll also have the chance to reshape how that wealth is invested, spent, and put to work. — Emma Burleigh, Fortune, 3 Sep. 2026

The United States lost thousands of lives and spent trillions of dollars in Afghanistan and Iraq, whereas the ongoing conflict with Iran has resulted in 18 American service members killed and has likely cost tens of billions of dollars. — James F. Jeffrey, Foreign Affairs, 3 Sep. 2026

Word History

Etymology

French, from tri- + -illion (as in million)

First Known Use

1745, in the meaning defined at sense 2

Rhymes for trillion

• billion
• million
• pillion
• castilian
• civilian
• cotillion
• pavilion
• postilion
• quadrillion
• reptilian
• vermilion
• vermillion

Kids Definition

trillion

noun

tril·​lion ˈtril-yən 

1

: a number equal to 1,000 times one billion see number

2

: a very large number

a trillion mosquitoes out tonight

trillion adjective

trillionth

-yən(t)th 

adjective

trillionth noun